The present invention generally relates to engines and more particularly relates to a seating contact between a component, such as an injector sleeve, and a cylinder head.
In an engine, certain components are mounted to a cylinder head above a combustion chamber. For example, in a fuel-injected engine, fuel injectors are seated against a cylinder head of the engine at desired locations for injecting fuel into the cylinders below. More particularly, known fuel injectors have an outer casing known as an injector sleeve that contact directly against a generally mated seating surface formed in the cylinder head. The seating surface is generally cooperatively shaped with the injector sleeve, e.g., frustoconical shaped. It is known to provide one or more raised annular ridges in the seating surface to cause a positive seal contact between the cylinder head and the injector sleeve, but these ridges have previously been located at a vertical midpoint of the sealing surface, substantially below an uppermost point of contact between the injector sleeve and the seating surface.
An upper end of the seating area is exposed to a water jacket of the engine. In the conventional system, a narrow crevice can form between the injector sleeve and an upper portion of the seating area. This crevice can be due to the static geometry of the seated structures, or the crevice can be caused by deflection during load cycling of components which are normally flushly seated in a static condition. Unfortunately, liquid coolant is drawn into the crevice and then forced out at high velocity or compressed during injector loading, causing cavitation damage, fatigue, and ultimately component failure.
Other components are known which have similar mounting structures. For example, a spark plug in a natural gas engine is known which has a seating geometry similar to that of the above-described fuel injector.
A need exists for an improved cylinder head seat assembly for a component, such as a fuel injector, spark plug and the like, which reduces cavitation damage.